Prostaglandin E1 in the cyclodextrin conjugate form (PGE1-CD) has been used in the treatment of peripheral arterial occlusive disease (PAOD). Because of the high rate of first pass metabolism in the lungs, PGE1 with lipid encapsulation (lipo-PGE1) can avoid this sequela. A double-blind, randomized, parallel, placebo-controlled group, dose response study to evaluate the safety and efficacy of IV lipo-PGE1 therapy in patients with ischemic ulcers is proposed.